similar to: adding 2 new functions to the AliasAnalysis interface

Hi, RFC Im adding 2 new functions to the AliasAnalysis interface: 1) ModRefSameBufferCheck: this function will receive 2 memoryLocation as parameters, and returns true if the parameters are modifying or refering the same buffer or same memory block, false otherwise. 2) getAddressesDistance: the function will recieve 2 memoryLocation, if they are mod/ref-ing the same buffer/memory block, the

Hello All, I have met a case with restrict keyword and I have a question about it. Let's look at a simple example. char buf[4]; void test(char *restrict a, char *restrict b, int count) {   for (unsigned i = 0; i < count; i++) {     *a = *b;     a++;     b++;     buf[i] = i;   } } I think there are no aliasing among pointers such as 'a', 'b' and 'buf'

On 11/17/2017 02:01 AM, Hongbin Zheng wrote: > Do you mean a and b are noalias if: > > static int foo(int *a, int *b) { > return a[0] + b[0]; > } > > int bar(int *x) { > return foo(x+1, x); > } > > ? > > To me, because "AA.alias((x+1, MemoryLocation::UnknownSize), > (x, MemoryLocation::UnknownSize)) != NoAlias", so a and b are not noalias.

On 11/17/2017 01:49 AM, Hongbin Zheng wrote: > Could you elaborate "Note that, without further analysis of the uses > of the potentially-noalias pointers, you can do this only ..."? > Why the uses, instead of the def, of pointer matter? Both matter. static int foo(int *a, int *b) { return a[0] + b[1]; } int bar(int *x) { return foo(x+1, x); } You can't mark a and

Am Mi., 18. März 2020 um 18:15 Uhr schrieb Chawla, Pankaj <pankaj.chawla at intel.com>: > > >> DependenceInfo is not using the AA interface correctly. Either DI has to be fixed, or another method added to AA that gives additional guarantees. Please see the bug report for details. > > Thanks for updating the bug report but GetUnderlyingObject() doesn't help in this case.

You might want to look more carefully at how you're constructing the MemoryLocation.   The first argument is a pointer, and the second argument is the number of bytes pointed to by that pointer (or MemoryLocation::UnknownSize if the number of bytes accessed isn't known). More generally, copy-pasting code you don't understand isn't a good idea. -Eli On 5/22/2018 4:02 PM, Dávid

Yeah, sorry for that. Better "It compiles ok (but maybe incorrect code)", not "It works" as I wrote. 2018-05-23 1:08 GMT+02:00 Friedman, Eli <efriedma at codeaurora.org>: > You might want to look more carefully at how you're constructing the > MemoryLocation. The first argument is a pointer, and the second argument > is the number of bytes pointed to by

On 07/14/2017 03:00 PM, Davide Italiano via llvm-dev wrote: > On Fri, Jul 14, 2017 at 12:50 PM, Nuno Lopes via llvm-dev > <llvm-dev at lists.llvm.org> wrote: >> Hi, >> >> I going through the alias analysis documentation >> (http://llvm.org/docs/AliasAnalysis.html) and noticed the following in the >> definition of PartialAlias: >> " >> The

IR: define i32 @calloc_strlen_write_between() { %call = tail call noalias i8* @calloc(i32 10, i32 1) store i8 97, i8* %call, align 1 %call1 = tail call i32 @strlen(i8* %call) ret i32 %call1 } static bool eliminateStrlen(CallInst *CI, BasicBlock::iterator &BBI, AliasAnalysis *AA, MemoryDependenceResults *MD, const DataLayout &DL, const TargetLibraryInfo *TLI,

Am Di., 17. März 2020 um 16:56 Uhr schrieb Chawla, Pankaj via llvm-dev <llvm-dev at lists.llvm.org>: > All I am expecting from DA is a direction vector containing (*). There seems to be a bug in DI, see Felipe's answer. > I think the main problem is that currently there is no exact way DA can query AliasAnalysis in a ‘conservatively correct’ manner. > > Using UnknownSize

+ a few others. After following this rabbit hole a bit, there are a lot of mutually recursive calls, etc, that may or may not do the right thing with vectors of pointers. I can fix *this* particular bug with the attached patch. However, it's mostly papering over stuff. Nothing seems to know what to do with a memorylocation that is a vector of pointers. They all expect memorylocation to be a

Okay, so then it sounds like, for now, the right fix is to stop marking masked.gather and masked.scatter with intrarg* options. On Mon, Aug 29, 2016, 1:26 PM Philip Reames <listmail at philipreames.com> wrote: > We might have specification bug here, but we appear to implement what we > specified. argmemonly is specified as only considering pointer typed > arguments. It's

It works with MemoryLocation MemoryLocation::get(const CallInst *CI) { AAMDNodes AATags; CI->getAAMetadata(AATags); const auto &DL = CI->getModule()->getDataLayout(); return MemoryLocation(CI, DL.getTypeStoreSize(CI->getType()), AATags); } Is it fine? :) 2018-05-22 23:56 GMT+02:00 Dávid Bolvanský <david.bolvansky at gmail.com>: > Looks like there are many overloads

Thank you all for your replies. So here seems to be an agreement that the documentation for PartialAlias is incorrect. Daniel: now you got me wondering about MustAlias. This is what the docs say: "The MustAlias response may only be returned if the two memory objects are *guaranteed to always start at exactly the same location*" This statement is regardless of the access sizes. For

----- Original Message ----- > From: "Daniel Berlin" <dberlin at dberlin.org> > To: "Philip Reames" <listmail at philipreames.com>, "Davide Italiano" > <davide at freebsd.org>, "Chandler Carruth" <chandlerc at gmail.com> > Cc: "Chris Sakalis" <chrissakalis at gmail.com>, "David Majnemer" >

Thank you for the quick fix, I can no longer reproduce the issue. As far a releases go, I am guessing that this is going to be in 4.0? Best, Chris On Tue, Aug 30, 2016 at 9:26 PM, Daniel Berlin <dberlin at dberlin.org> wrote: > Yeah, i just hope it doesn't regress scatter/gather vector code badly. > But at least it's correct now? > > > On Tue, Aug 30, 2016 at 1:11

Great, thank you! On Wed, Aug 31, 2016 at 2:07 PM, Hal Finkel <hfinkel at anl.gov> wrote: > > ------------------------------ > > *From: *"Chris Sakalis" <chrissakalis at gmail.com> > *To: *"Daniel Berlin" <dberlin at dberlin.org> > *Cc: *"Hal Finkel" <hfinkel at anl.gov>, "David Majnemer" < > david.majnemer

this is definitely a bug in AA. 225 for (auto I = CS2.arg_begin(), E = CS2.arg_end(); I != E; ++I) { 226 const Value *Arg = *I; 227 if (!Arg->getType()->isPointerTy()) -> 228 continue; 229 unsigned CS2ArgIdx = std::distance(CS2.arg_begin(), I); 230 auto CS2ArgLoc = MemoryLocation::getForArgument(CS2, CS2ArgIdx, TLI);

Dear llvm contributors, Could you please advise me where objects of MemoryLocation class are created for ‘llvm.memset.*‘ intrinsics? In the Bug 23077 (https://llvm.org/bugs/show_bug.cgi?id=23077) the AliasSetTracker constructs 128 alias sets for 0 pointer values, which contain only unknown instructions. In this case, all unknown instructions, which are added to new alias sets in the

2015-12-11 23:44 GMT+05:00 Hal Finkel <hfinkel at anl.gov>: > Hi Roman, > > The MemoryLocation objects are involved in findAliasSetForUnknownInst, but none are created there for the memset intrinsic. MemoryLocation objects are only involved for the regular memory accesses being compared to the unknown instruction. See AliasSet::aliasesUnknownInst in lib/Analysis/AliasSetTracker.cpp.